The Crystal Structure of Human α2‐Macroglobulin Reveals a Unique Molecular Cage

I'm your Venus: The crystal structure of the human methylamine-induced form of α2-macroglobulin (α2M) shows its large central cavity can accommodate two medium-sized proteinases (see structure, front part clipped off to better show central cavity). Twelve major entrances provide access for small substrates to the cavity and the still-active trapped "prey". The structure unveils the molecular basis of the unique "venus flytrap" mechanism of α2M.